#include<iostream>
using namespace std;

double getSum(int n)
{
	double result = 0.0;
	for (int i = 1; i < n + 1; i++)
	{
		//result += 1.0/i;
		result += static_cast<double>(1) / i;
	}
	return result;
}
int main()
{
	int n = 0;
	cin >> n;
	cout << getSum(n) << endl;
	return 0;
}